will it work (repair question)?

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we built a wood top for a semi-local client of ours a little more than a year ago. the wood, white oak, came in heavy and seemly wet but our promised deadline had us build the top from it regardless (and i really knew better but figured we would be okay). anyways, i just got this picture from the homeowner. obviously, we need to make a repair.

i'm thinking about running a circular saw blade into the broken joint and adding a solid piece to fill the void left by the saw kerf. sand and reshape the edge profile. recoat with mineral oil. i'm planning my attack in the spring. this is a quick explanation so please don't make too many assumptions regarding my quality. we do work for other cabinet shops and our quality is always noticed.

"Our quality is always noticed" Is that a good thing or bad thing? Just kidding - could not resist.

I've been there. Your repair idea is sound - I use epoxy to glue the wood in place, but tape off the surrounding area real close to the cut. Better yet, tape it and then cut. The epoxy does not require pressure to bond.

One problem we have found is that the mineral oil is along that crack, and down in the wood by 1/16" or so. You can't get away from it, so the glue does not want to bond on that upper edge, no matter what. We are considering giving up on these tops since they seem to be prone to developing problems.

What is the RH of the house? Spekva calls for a minimum of 40% RH. That will grow mold in my area. I bet it is under 25%

You may be better off waiting until late Summer to do this - let it move back/close up a bit. If you fill it while shrunk (today), then when it expands again (summer), it may split since it cannot move back into the previous - now filled - space.

One repair I learned was to do the main repair from below. Either epoxy as david said or drill and install several dowels along the center crack line from below to within 3/16 of the top surface. This repair will provide the stability. Then use a product like a Mohawk colored burn-in stick or kneaded epoxy from the top to repair the surface. Seems like the less you disturb the top surface the more likely you will have an inconspicuous repair. I have seen some incredible repairs and the grain of oak should be more forgiving.

thanks for the replies. we've done a few hundred tops and this is the only one we've had problems with. in november, we found out that the homeowners hadn't been oiling the top (it was installed 2/14) so i'm not 100% sure who is to blame but i've signed up for the fix.

david - thanks for the reminder with the oil. i know this and have instructed her to lay off the oil in this area until we make the repair. i would guess the epoxy might stick to itself and fill the void at the top (even though it wouldn't be holding the wood together)? also, this is an edge grain top so the width of the boards is expanding more in thickness than in width. i may still wait until summer but i think we would be okay to make the repair in the spring. house is in north carolina.

I sure wouldn't blame the customer for not oiling, when you admit the moisture level was probably off. Sounds to me like you played with fire, and got burnt. I'd also say that oiling the wood doesn't make any difference anyway. Wood sitting around the shop doesn't crack, and it's never had oil. Oil, or any finish, doesn't make up for breaking rules of solid wood construction.

White oak does do that.
I've had the best luck by ripping the crack and edge gluing the two pieces. This is the only 90% + successful solution that I've found. Yes you lose 1/8".
On short cracks a biscuit made of the same wood species at 90° to the crack has worked as well for square of rectangle tops in 70% + of the cases. I have not tried this on a round top. The real fear is that another crack may open up. it's the nature of the beast..

Rip along the crack joint the edges and re-glue. You may have to reduce the radius a fraction and run the edge again but that is pretty simple. With that said:

I had a similar experience years ago making a table top from a heart pine beam I re sawed. It buckled after a few months. I acclimated the boards properly this time and made the customer a new top without question. They were also able to continue to use their table without interruption.

Like you, I screwed up, not the customer...
You should make them a new one.

Both cracks are on glue lines. I would question your glue-up process. The glue line should be stronger than the surrounding wood.
I second the motion to rip the panel, joints and reglue.
Another note; I don't consider mineral oil a wood finish. According to Bruce Hoadley it provides no moisture resistance and just collects dust and grime. Danish oil is marginally better - it at least has some varnish in it.

thanks again everybody. the picture i have of the entire job is too large for woodweb but you're looking at a small part of a 160" x 48" x 2.25" countertop. it has a gas range at one end. aside from its size and the cooktop - i'd love to be able to "do it right" and bring it back to the shop.

tom - i'm really not sure the difference from being right in the glue line and very, very close to it (indistinguishable without powered magnification) . our prep was the same for all joints and all of the material was run at the same time. it is an edge grain top so the glue surfaces were planed, then ripped and stood on end. i would think we'd have problems everywhere if we inadequately/incorrectly prepared the surfaces. and experience and validation by hundreds of other jobs leads me to believe this is not the culprit.

with food safe mineral oil, yes, i agree, a very poor "finish". easy to refresh and fda approved for food contact are the main reasons we use it (when requested). i'm pretty sure danish oil isn't fda approved and in our litigation-happy world - can you really risk your business by going with a unapproved product (referring to direct food contact finishes only)?

The image shows a crack right next to a glue joint. Possibly a result of PVA glue moisture and the repair was a spline set in with a biscuit joiner and clamped worked ok and I may have an image of the completed top as well.

When I had a glue line open (on air dried white oak coincidentally) it was due to over tightening the clamp on the end of a table top. I likely starved the glue line and the stress associated with differential drying of wood between exposed end grain and towards the core caused the failure. I have returned to the old school technique of springing my glue joint on solid glue-ups of any significant size. Extra down pressure on the wood midway through edge truing easing off at ends. Keep your jointer super sharp. I resist the temptation to just glue it and squeeze it if there is resistance to the joint to coming together in a dry fit.
That said, an on site hand-planed wedge and Titebond II after swabbing the joint liberally with rubbing alcohol or acetone to remove oil would do the trick.

I'm actually surprised by the sheer size of your solid-slab glue-up that you haven't had more failures on the rest of them. I wouldn't have the balls to guarantee anything remotely like this. Just sunlight shining on half of it through a window is going to make it move and move a lot. If I were you I'd start thinking about leaving town (just kidding) .

Seriously, fix it anyway you can but don't think for a second that your "Dutchman" patch is going to please anyone. Geeze man, even concrete requires expansion joints and engineered floor tiles and plank need room to move.

I'm sorry but a big glue-up like this (especially on oak) is only practical and proper when manufactured as "butcher-block". I would rethink and re-engineer your product if I were you.

thanks for the kind words. we've had plenty of success with large glue ups as a lot has to do with installation. again, this is our only failure out of a few hundred and the only one that "could" be our fault. i haven't checked the installation and the homeowner already admitted not oiling the top for 6-8 months.

what do you mean by "butcher block"? i'm familiar with the term but it is often misused or used in place of wood countertop. this is an edge grain top (as stated above) so the majority of the expansion/contraction will take place in thickness, since the pieces have been turned on edge. we've done plank constructed tops at much larger widths (93" is our widest to date) without issue.

i'd prefer to keep this less about what a dummy i am and focus to technical merits of my proposed fix. i'm married so i'm well aware of my shortcomings!

No disrespect intended, I don't know your methods but you obviously do. I would be afraid to do thisyself with no traditional joinery or anything other than a bit of glue to keep things together. Are there any transverse splines or perhaps interior threaded rod? I see no splined end-capping either, just exposed end- grain with the customers' job to keep it oiled and sealed?

It's the size of these slabs which scares me. Any open joints along the edge spoils the whole enchilada. Can you honestly say that you're not a little apprehensive about all the rest?

When we make these, they are often 2" thick or better. We will rip 8/4 rough to 2-1/4" then face and edge on a joiner, then plane to a consistent 1-3/4" x 2". We then match up for grain or randomness, and glue in one or more sessions, using bar clamps. If we start with flat sawn lumber, then the 'edge grain' that makes the surface is more like quartered or rift. This is the most common type we are asked to make.

We also do end grain tops, where all the upper surface is the end of what is essentially short blocks of wood. 1-3/4" x 2-1/4 x 3" long blocks. We will glue long strips, then send them all thru the planer - on the 'side grain' sides - to level all the joints, then glue for the other dimension.

The end grain is like the true original block that the butchers used for chopping up animal parts. Maple is also traditional for that use, and it was made with end grain since it is easier on the knife edges. A few cracks did not present a problem. If iron rods were used, they could also go thru the long leg tenons to help keep them in place during rough daily use.

Iron rods or similar have been suggested in previous Woodweb and other discussions on wood tops. To 'keep them from splitting' or to 'prevent warp' or other wishful thinking. If you think thru seasonal movement, you will see that rods will do more harm than good, unless they are allowed to completely float.

The tops will still move a considerable amount with changes in RH. A quick look at the Shrinkulator will help indicate what that movement may be on a seasonal basis.

What caused Mr Google's open crack? Can't say. I'd lean towards lack of glue on one bit of one edge. Maybe starvation with 'too much clamp pressure' (please define?). Maybe too high a moisture content. Likely since we are seeing the opening at the end grain, where wood loses /gains moisture more rapidly. Or something else. Or - most likely - two or more of the above.

To David R Sochar: Okay I've been caught using terms I don't fully understand. I have never really understood the concept of "glue starvation". In theory I suppose it means that excessive glue pressure squeezes all or too much glue from the surface leading to a failed bond. In practice we all try for an imperceptible glue line - zero thickness? My experience with solid glue-ups and veneer too much pressure leads to local failures. Defining too much clamp pressure? I don't know I just yell not that tight! It depends on surface area, edge prep, tolerance...
To the original poster: Seeing as you have had a 100+ successful tops I know you don't need any advice on assembly but I am curious about your process and machinery.

dave - glue starvation might the be answer. i have had to remind my guys about not tightening the clamps and then untightening them to make adjustments during glue up. they know this is bad stuff but occasionally forget. the other part is that we essentially start at one end and work our way down. if we don't move fast enough the glue can slide onto the floor, leaving little to hold the pieces together. neither is a day-to-day worry but either, combined with slightly damp wood, could be the culprit for this top.

I wanted to comment about how fantastic your countertops look. i can see why you've made so many of them...I'll take two. The glue-ups truly are ambitious but that's what make these so special. Wood is good no matter how you slice it and you're cutting no corners that I can see. I love your work and apologize for critical comments. You obviously know your stuff.

I think the method you describe early in this thread about running a circular saw over the particular split on joint then filing it with splinter and using an epoxy adhesive may be your best quick fix option because to do it properly by re-ripping it along the joint and re-gluing it you would actually lose 1/4" because as you can see there is another crack developing along another joint which moisture Is definitely going to widen unless sealed properly. Your finisher may need to aesthetically 'touch up' the surface of the repair area so that there are no small crosscut kerf lines indicating a saw blade was there and everything just blends in one direction.

The problem with this type of construction is that the length and weight of this entire build. Youre treating this countertop like a massive butcher block and using the same joining and finishing techniques that would be used on a small 12"x12" board. And even those boards can split and warp because they're never sealed completely. You can't as they are food grade functional.
This thing is massively bigger in size and used as a countertop which is prone to unequal wieght stresses imposed upon it, heat, water, etc. and all this without dowel or some type of tenon joinery which kudos to you is all pretty incredible. I think however that you need to ditch this mineral oil finshing stuff and finish these pieces properly. They are too big and heavy to treat like they're simple cutting boards. If you want to go less toxic, use a water based sealer but seal them like you would any heavy duty piece of wood furniture. They are beautiful tops and I doubt that customer is going to start carving food or cutting vegetables directly on them. Are they really going to want to look at knife marks permanently cross stamped every time they look at their countertop? That's what cutting boards and butcher blocks are for. Leaving anything to the responsibility of the customer that affects the actual structure of your product (not just minor aesthetics like dry looking leather) is not good business in my opinion.

I have huge sympathy for you, and have been there myself. If you work with wood long enough, you'll bump into failure at some point. Sounds like your record is pretty dang good.

Lots of good suggestions. I would underscore those that have you ripping along the cracks, and regluing - if you are lucky, those wont carry through the length of that monster. Sharp blade in a tracksaw would obviate transportation, change in moisture, etc, problems.

A couple of questions I haven't seen. Forgive me if I am duplicating:

* Is the circular end sitting on a solid panel, or is it open underneath like an apron? You could have moisture transfer issues.

* Is it fastened down in such a way as to restrict movement? Some guys would be tempted to put screws at 3 and 9 oclock, which would pretty much guarantee cracking.

* Is the panel balanced? I realize oil is not quite the same as lacquer or varnish with regards to transfer, but it is still a consideration, and I would want top and bottom coated similarly.

At any rate, it is definitely salvageable, in my opinion. One in a hundred is rate I certainly wouldn't be ashamed of. Best of luck.

i don't know anything about the conditions of the install as we didn't install it. obviously, when i make the repair, i'll address anything done incorrectly then.

i've always wondered about balancing the panel with mineral oil. we certainly apply oil to both sides before it leaves the shop but most applications would make it very difficult to reapply oil to the bottom side. i guess it migrates through the wood with the help of gravity? we've done plenty of mineral oil tops without other problems and i seriously doubt anyone is oil the bottom side.

I hate these kinds of problems. Last fall I posted a problem I was having with the application of paste wax to a top I installed by a well-meaning cleaning person. It wasn't my fault, but I ended up choosing to refinish anyway, so as to protect my reputation and my relationship with the contractor. Cost me a few hundred bucks, and I was irritated as heck about it. But what do you do?

Anyway, while I would agree with Rick S. that you may have starved the joint by over clamping, or by forcing that end closed when it might not have been joined as straight as you would like, I think it is also possible that you have problems associated with the install. Especially since you do a lot of these and have a really high rate of success. A clamping issue would certainly be an anomaly. I would bet, for instance, that there are one or more screws than there should be, in places where they shouldn't be. I would also bet that the plywood circle your top is sitting is not only solid, but has finish on it, as well. As for oil and panel balancing, I don't know either - I was just thinking about it.

Anyway it sounds like the customer is one of those you like to have in situations like this - willing to wait on the proper solution.

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